Request for Clarification on binderfs Support on NVIDIA Thor

Autonomous Vehicles DRIVE AGX Thor DRIVE AGX Thor General
1

DRIVE OS Version: 7.0.3

Issue Description: Clarification Needed: binderfs Support on NVIDIA Thor Kernel (Binder IPC Available but binderfs Mount Fails)

Hello NVIDIA team,

I am currently evaluating Android-related IPC mechanisms on a Thor-based platform and need clarification regarding binderfs support in the Thor kernel.

1. Kernel configuration shows binderfs enabled

After building the Thor kernel, I verified that the following configuration options are enabled:

CONFIG_ANDROID_BINDER_IPC=y
CONFIG_ANDROID_BINDERFS=y
CONFIG_ANDROID_BINDER_DEVICES="binder,hwbinder,vndbinder"
CONFIG_USER_NS=y
CONFIG_PID_NS=y
CONFIG_NET_NS=y
CONFIG_UTS_NS=y
CONFIG_TIME_NS=y
CONFIG_IPC_NS=y

The kernel image was successfully built and flashed onto the Thor hardware without errors.

2. Binder IPC works on the running system

Binder driver appears to be available:

cat /proc/filesystems | grep binder

Output:

nodev  binder

Binder device nodes also exist on the system:

ls -l /dev | grep binder

This confirms binder IPC is operational.

3. Legacy binder mount works, but binderfs mount fails

When I try to mount binder using the legacy binder filesystem:

sudo mount -t binder binder /dev/binderfs

This succeeds and exposes:

/dev/binderfs/binder
/dev/binderfs/hwbinder
/dev/binderfs/vndbinder
/dev/binderfs/binder-control
/dev/binderfs/features/

However, attempting a binderfs mount fails:

sudo mount -t binderfs binder /dev/binderfs

Result:

mount: /dev/binderfs: unknown filesystem type 'binderfs'.

This seems to indicate that binderfs is not registered as a filesystem type, even though CONFIG_ANDROID_BINDERFS=y is enabled and the kernel was rebuilt and flashed.

4. Question: Is binderfs supported on Thor, or is additional configuration required?

I would like to clarify:

  1. Is binderfs expected to work on Thor-based kernels?
    The documentation suggests binderfs should be available when CONFIG_ANDROID_BINDERFS=y, but the runtime behavior indicates otherwise.

  2. Is there any additional kernel configuration, patch, or security setting required to enable binderfs registration?

  3. Is binderfs intentionally disabled or restricted on Thor?
    (e.g., only mountable in init_user_ns, restricted by LSM, or not exposed in this BSP)

  4. Could there be any additional steps required during kernel flashing or bootloader configuration to ensure binderfs support is active?

My goal is simply to verify whether binderfs should be available on Thor platforms, and what is required (if anything) to enable it properly.

Any guidance or clarification from the NVIDIA kernel or BSP team would be greatly appreciated.

Thank you!

6

Dear @mykhailo.i.kozak ,
Let me confirm internally on the binderfs support on P3960. Mean while, could you please share the complete followed steps in building kernel image and flash?

7

Binderfs is now mounting correctly on Thor.
The root cause was that the target filesystem did not get fully updated after the kernel rebuild—some steps in the image rebuild and flashing process were skipped. After properly regenerating and flashing the updated kernel and filesystem, binderfs worked as expected.

8

Dear @mykhailo.i.kozak ,
Glad to hear the issue is fixed.
Could you please share the steps as reference for other in community.

10

After the custom kernel is built, make sure you rebuild CUSTOM FS /LINUX FS without #–skip_if_exists option

/drive/drive-linux/filesystem/create_linux_targetfs.sh -t thor #–skip_if_exists